1. Field of the Invention
The present invention relates in general to spray valves affixed within the tops of aerosol cans for the purpose of generating and delivering a mist of spray from the interior of the can to a nozzle of the spray valve. More particularly, the present invention relates to a tilt type of spray valve assembly which is actuated by an automatic actuator.
2. Description of the Prior Art
It is often desirable to attach automatic spray actuators to aerosol cans having integral spray valves. The automatic spray actuators can, for example, intermittently actuate the spray valve for predetermined time periods at predetermined intervals, as may be necessary in the dispensing of insecticides. However, difficulties have arisen in the design of the actuators due to the spray actuation characteristics of the spray valve of the aerosol cans. For example, it is desirable to minimize both the stroke distance for actuating the spray valve and the amount of pressure which must be applied by the automatic actuating device, since reduced stroke and pressure result in smaller and simplified structures for the automatic actuating devices.
It has been known to provide automatic actuating devices for spray valves of aerosol cans in which the automatic actuating devices tilt, rather than depress, the spray valve. However, known tilt-type spray valves were designed for manual finger operation, rather than the precise and rigid requirements of automatic actuating devices. Therefore, under repeated automatic actuation, they suffered from several shortcomings. First, the output stem of the tilt-type spray valves were made of semi-rigid plastic material supported by a flat rubber or neoprene disk-like washer retainer. The output stem distorted in shape after several cycles of operation and could no longer retain its shape or vertical position within the can valve opening. Therefore, the output stem tended to remain in the tilted or "on" position of actuation and failed to shut off the output flow from the pressurized can. Moreover, the nozzle spring and seal design of the known tilt-type valve assemblies required a considerable amount of pressure for actuation, resulting in the aforementioned increase in size and complexity for the automatic actuating device. Finally, the known spray device is required a long lateral stroke for full spray output operation of the nozzle. This long lateral stroke not only required a more complex actuator, but also greatly reduced the activation sensitivity of the spray valve assembly. A further problem associated with the long lateral stroke was that the round stem hole of the neoprene output stem seal became distorted and elongated, thus permitting leaking of pressure and liquid from around the valve stem at the point of exit through the seal.
It is therefore desirable to provide a spray valve for an aerosol can which is simple in construction, inexpensive to manufacture, reliable in operation and compatible with automatic actuating devices.